But that also comes at a cost of decreasing the amount of revenue it actually gets from each premium subscriber. In the filing, Spotify indicates that the fee for a family plan — which costs $14.99 per month — can be actualized over as many as six accounts total (though it might not always be six).

The premium user consists of the one master premium account, which pays for the subscription, and up to five sub-accounts for family members. Spotify is also pointing to its student plan, which costs $4.99 a month, as another contributing factor to those pressures. This means that even though Spotify is gathering more premium users, the actual revenue it generates from those users can drop over time.

And, indeed, that’s what’s happening, according to the filing. Spotify said its premium average revenue per user was around €5.24 in 2017, compared to €6.00 in 2016 and €7.06 in 2015. Spotify recognizes in the filing (“Family Plan” is mentioned nearly three dozen times) that this is partly due to the family plan.

But at the same time, churn — a significant metric for subscription services that shows how many users are coming and going — is dropping each year and the number of hours users are listening are significantly increasing. Churn was 7.5 percent in 2015, and it’s down to 5.1 percent in 2017; content hours have more than doubled in that time, from 5.4 billion hours to 11.4 billion hours.

Here’s the boilerplate from the filing:

The rate of net growth in Premium Subscribers also is affected by our ability to retain our existing Premium Subscribers and the mix of subscription pricing plans. We have increased retention over time, as new features and functionality have led to increased User engagement and satisfaction. From a product perspective, while the launches of our Family Plan and our Student Plan have decreased Premium ARPU (as further described below) due to the lower price points per Premium Subscriber for these Premium pricing plans, each of these Plans has helped improve retention across the Premium Service. As a result, while Premium ARPU declined by 9% from 2015 to 2016 and 14% from 2016 to 2017, in part due to the launch of the Family Plan in 2016, Premium Churn declined by 1.1% from 7.7% in 2015 to 6.6% in 2016 and declined by an additional 1.1% from 6.6% in 2016 to 5.5% in 2017. With the growth in higher retention products, such as our Family Plan and Student Plan, we believe these trends will continue in the future.

All this is more or less part of a long game for Spotify, which is looking to go public in the U.S. amid significant and increasing competition for premium subscribers from companies like Apple or Google.